The proposed study will allow the current DSM-IV categorical model of personality disorders to be compared directly to the Five-Factor model (FFM) of personality, on the basis of temporal stability within a clinical setting, convergent and discriminant validity, and clinical utility. The FFM is the most heavily researched of the dimensional models that have been proposed as an alternative for the current DSM-IV system. The DSM- IV and FFM ratings will be assessed in a group of 75 self-referred individuals who are currently receiving outpatient psychotherapy for a personality disorder using the four primary methods of assessment used in clinical practice: unstructured clinical interview by the client's therapist, semi-structured interview by a trained researcher, self-report inventory and informant report. Additionally, the same participants will be assessed again after six months to examine the temporal stability of each model. Finally, the therapists who are treating these clients and providing the unstructured clinical interview ratings will also provide feedback on the clinical utility of each model. It is hoped that this research will help to better conceptualize personality difficulties and ultimately a more coherent and useful diagnostic system.